In recent years, the spread of a mobile terminal such as a cellular phone is remarkable. Of them, a slide type mobile terminal device of a shape that makes two cases slide in order to improve portability and operability, is widely used.
A mobile terminal device of such slide type, for example, is disclosed in patent literatures 1 and 2.    Patent literature 1: Japanese Patent Laid-Open No, 2003-179674    Patent literature 2: Japanese Patent Laid-Open No. 2003-319042